bcm29 Flashcards
how gluconeogenesis by pass the two irreversible steps of glycolysis?
using different enzymes
Fructose bis phosphatate
pyruvate carboxylate (pyruvate ->oxalocacetate)
pep carboxylase oxacloacetate -> pep
what does gluconeogensis allow?
cell to make glucose from protein but not lipid
starvation response.
how do plants make lipid-> glucose
use glycoylate cycle
short cut
where does glycoxylate cycle occur
specilised peroxisomes called glyoysomes
found in seedlings so fat can be used for cell walls
what is the pentose phosphate pathway
mulitfunctional shunt anabolic shunt from glycolysis
what is the first stage of the pentose phosphate pathway
oxidation step
generates NADPH
glucose 6p> gluconate 6p > ribulose 5-p
what can be made from the ppp
nadph for lipid synthesis
ribulose bp for dark reactions of photosynthesis
ribose for rna and dna synthesis
gap, fructose p and fructose 6p for glucose
what are the two main stages of the pentose phosphate pathway?
oxidative stages generate nadph
non oxidative stage makes 5 carbon sugars
how does metabolism differ from what would happen anyway?
conserves free energy as atp iin a way burning glucose in o2 doesnt and flux is faster at 298k
what is flux
carbon flow
what does rate of flux depend on
enzyme availibity and activity
what happens to flux if there is no pfk activity
still some flux if o2 is presetn as in high o2 reactions of glycolysis krebs and op are all spontaenous
what does existence of flux depend on
thermodynamics
what does enzyme regulation maintain
homeostasis in the face of externally imposed changes in flux
what do all metabolic processes depend on
thermodynamic disequilibrium
